Intake manifold structure



Oct. 2, 1956 P. M. ROTHWELL 2,764,961

INTAKE MANIFOLD STRUCTURE Filed July 25, 1954 4 Sheets-Sheet 1,qrrarkz/s Oct. 2, 1956 P. M. ROTHWELL INTAKE MANIFOLD STRUCTURE FiledJuly 23, 1954 4 Sheets-Sheet 2 34 71172;? M FaZlwe/Z szdzw) I L 0a. 2,1956 P. M. RQTHWELL 2,764,961

INTAKE MANIFOLD STRUCTURE Filed July 23, l954 4 Sheets-Sheet 4 II/l IIII INVENTOR. 1%; M/Baiizz/e/Z United States Patent INTAKE MANIFOLDSTRUCTURE Philip M. Rothwell, Detroit, Mich., assignor to ChryslerCorporation, Highland Park, Mich., a corporation of Delaware ApplicationJuly 23, 1954, Serial No. 445,225

15 Claims. (Cl. 123-52) This invention relates to intake manifoldstructures for engines of the type having a pair of cylinder banksarranged at an angle to each other and especially for V engines.

My invention has particular application to improved intake manifoldingfor V8 engines wherein two inner cylinders of one bank of the engine andtwo outer or end cylinders of the other bank of the engine are fed froma common supply of air fuel mixture.

It has heretofore been proposed in V-8 engines of the foregoing type tofeed the engine from one dual barrel carburetor, each barrel of whichfeeds four cylinders. Although good performance is thereby possible, itis desirable in certain installations such as for truck or industrialuse to obtain optimum mid-speed torque and I have discovered thatimprovement in this feature of the engine performance is feasible whilealso providing greater air fuel capacity for the engine by a manifoldhaving a novel arrangement of passages and which employs two simple,inexpensive, single barrel carburetors and in the Widest possiblespacing, such that the use of large air cleaners becomes possible.

The use of two individual carburetors is advantageous since the barrelsof a dual carburetor even if of the same size are interconnected partway, i. e. in the sense that they employ one air cleaner and one airhorn and I find that the effective air-fuel capacity is not as great asthat obtained by the use of two single carburetors. In fact even if theair capacity of the total system at high speed (volumetric efliciency)were as a practical matter the same in the case of the dual or twosingle carburetors or greater in the case of the dual I find thatmid-speed torque will be greater in the case of the two singlecarburetors.

I have further discovered that although the wide spacing of theindividual carburetors produces a wide variation in conduit lengths fromthe carburetor riser to the cylinders, such does not adversely affectpower output or air-fuel distribution in the mid-speed range in whichthe engine must do its principal work in the case of trucks orindustrial use and good performance with a good F/ A ratio of about .080in all cylinders is obtainable. This is believed due in part to asatisfactory pulsating flow set up in the conduits and the frequency ofwhich at the engine speeds 600-4000 R. P. M. and especially in themidspeed range of 2000-3200 R. P. M., in which peak torque output isdesired, is not adversely affected by the different pipe lengths of thebranches and in part to the fact that my air-fuel conduits directlyconnect with the manifold intake risers to provide better distributioncontrol than Where the cylinders must be fed off side branches.

The principal object of my invention is therefore to provide engines ofthe foregoing type with an intake manifold system providing goodmid-speed torque output.

Still another object is to provide engines of the foregoing type with anintake manifold system providing optimum torque in the speed range of2000-3200 R. P. M.

A further object is to provide an engine of the fore- 2,764,961 PatentedOct. 2, 1956 2 going type with an intake manifold system utilizing apair of spaced single barrel carburetors and whose firing order providesthe widest possible separation between suction impulses on the twocarburetors.

A further object is to provide such engines with an intake manifoldsystem using a pair of single barrel carburetors arranged with thewidest possible spacing and utilizing large air cleaners.

In working with the manifold of my invention, I have found that due touse of a simple form of carburetor that there is tendency for somecylinders to over enrich at certain low speeds, for instance, 1600 R. P.M. possibly due to high pulsations, and such tends to foul up plugs. Ihave found that this condition may be controlled at the expense of sometorque output reduction by the use of special carburetion. However, thisis expensive. I have found that the condition may preferably becontrolled by the use of conduit-type metering means between themanifold intake risers to damp out high pulsations and thereby preventover enrichment. The metering control means may be constituted of asingle or plurality of conduits whose total area is somewhat critical inthat if too large, the value of a firing order producing a wideseparation in suction impulses may be somewhat lost with consequent lossof torque. No fixed formula for this area appears possible and hence itis recommended that several sizes be tried to find that which providesthe best mixture control and best torque. In general an area of lessthan /2 sq. in. is preferred. An area of 0.3 sq. in. appearssatisfactory for a 331 cu. in. V-8 engine using standard single barrelcarburetors, for instance Ball & Ball BBS975S carburetors.

Hence a further object is to provide a manifold system as aforesaidwherein pulsation damping or mixture metering control means are providedbetween the intake riser passages of the manifold.

I have further discovered that with-a manifold such as I employ, heatingof the intake riser passages for normal operation may advantageously beprovided by water heating. In the present manifold it is simpler toprovide than exhaust gas heating and is practical in the case of truckengines or industrial use because in these operations the operator cantake more time for warm up. Moreover, water taps are readily availablein the cylinderheads. Furthermore, by using Water heating therefrigeration effect of the air fuel mixture on the water is obtainedand this thereby reduces the heat rejection of the coolant waternecessary at the radiator.

Hence still another object of my invention is to provide an intakemanifold system as aforesaid in which the intake riser passages arewater heated for normal operation and for reducing the heat rejection ofthe coolant system at the radiator.

Other objects and advantages of my invention will be more apparent fromthe following description of a preferred embodiment of my invention asapplied to a 331 cu. in. V-8 engine, reference being had to theaccompanying drawings in which:

Figure l is an end elevational view partly in section of an 8-cylinderV-type overhead valve engine embodying the intake manifold system of myinvention, the section through the manifold being taken approximately atZZ of Figure 2;

Figures 1A and 1B are schematic views of the two preferred two planecrank pin arrangements for an 8-cylinder V engine utilizing myinvention, the Roman numerals in the figures indicating the positioningof the crank throws counting from the front or fan end of the engine andthe numerals in the brackets indicating cylin der numbers whose pistonsare connected with the engine throw;

Figure 2 is a plan view of the manifold of my invention andschematically showing the banks of cylinders in relation thereto;

, Figure 2A is a schematic showing of the air-fuel passages of themanifold of Figure 2;

Figure 3 is a side elevational view of the manifold of Figure 2 showingthe carburetors and air cleaners in position thereon;

Figure 4 is a sectional development taken in elevation at A'A of Figure2 through a pair of conduits connecting with one manifold riser passageand showing a portion of the throttle passage of a carburetor feedingthe same; I

Figure 5 is a sectional development taken in elevation at BB of Figure 2through a second pair of conduits connecting with the same riser;

Figure 6. is, a sectional development taken in elevation at C'C ofFigure 2 through a pair of conduits connecting with the other manifoldriser;

Figure 7 is a sectional development taken in elevation at D'-'D ofFigure 2 through a second pair of conduits connecting with the sameriser passage as the conduits of Figure 6 and showing the throttlepassage portion of the carburetor feeding the same;

Figure 8 is a sectional elevation taken at E-E of Figure 2 through theriser passages and longitudinal water heating conduit;

.Figure 9 is a sectional elevation taken at FF of Figure 2 through onetransverse water heating passage; I Figure 10 is a sectional elevationtaken at GG of Figure 2 through a second transverse water heatingpassage;

Figure 11 is a plan view of a portion of the manifold of Figure 2showing a modification providing metering means between the carburetorriser passages; and

Figure 12 is a sectional elevationof portions of the riser passages ofthe manifold of Figure 11 taken at thereof showing the manner ofproviding metering means therebetween.

Referring now to the drawings wherein similar numerals are used todesignate similar parts of the manifold structure and system of myinvention, I have illustrated my invention asapplied to a 331 cu; in. 90V-8 engine of current manufacture having a so-called two-plane 90crankshaft, hemispherical combustion chambers and proyided withdowndraft carburetion of the single barrel type, each carburetor beingarranged reread a pair of inner cylinder of one bank and a pair of outeror end cylinders of the opposite bank. -It be understood that myinvention is applicable to other engines of the type having oppositebanks of cylinders and having a greater or lesser nurnber of cylindersAlso the carburetion may be of the downdraft, updraft, horizontal orinjection character.

As seen in the drawings, especially Figures 1 and 2, the engine has twobanks 9 and 9a of cylinders 10, four in each bank, arranged at 90 in acylinder block 11, to which cylinder heads 12 and 1221 are secured andprovided with hemispherical typecombustion chambers 13 immediately aboveeach cylinder 10. The cylinders of each bank are aligned longitudinallyof the axis of the engine and the cylinders of the opposite banks areoffset longitudinally relative to each other.

For convenient reference, the cylinders of the lefthand cylinder bank,which is to the left looking forward from the flywheel end of the engineare numbered 1, 3, 5, and 7 respectively, starting such numbering at thefan end of the engine, and those of the right-hand cylinder bank arenumbered 2, 4, 6, and 8 respectively, these numbers appearing internallyof the cylinder representations in Figure 2.

Each cylinder is provided with a piston 14 recipuocable therein andoperably connected to a crankshaft 15 through a connecting rod 16 andwrist pin 17. Crankshaft 15 may be of any of the conventional types butpreferably as seen in Figures 1A and 1B is an inherently balanced shaft,for example, a two-plane crankshaft wherein the double crank throwsidentified by the Roman numerals I, II, III, and IV are arranged 90apart, with throws I and II being respectively opposite throws IV andIII. Throw No. I of Figures 1A and 13 connects with the pistons ofcylinders l and 2, throw II with the pistons of cylinders 3 and 4, throwNo. III with the pistons of cylinders 5 and 6, and throw No. IV with thepistons of cylinders 7 and 8. In Figure 1A itwill be seen that throw No.III will follow throw, No. I by 90 of crank rotation counting clockwisein that figure and by interchanging throws II and III as in Figure 1B,throw No. II may be arranged 90 of clockwise rotation from throw No. I.

Various firing orders are possible for the two described crankarrangements while affording preferred feeding intervals in the intakemanifold of Figure 2. For example, the following firing orders:

may be used with the crank arrangement of Figure 1B.

In Figure 2 my invention has been shown as applied to an engine having acrank arrangement of Figure 1A and preferred firing order ofl-8-4-3-65-7-2. The firing sequence is designated by the numerals justoutside the ellipses in this figure designating cylinders. In thisstructure it will be apparent that the suction strokes of cylinders 1and 6 are 360 out of phase, i. e. the cylinder 6 is beginning itssuction stroke as the cylinder 1 starts its power stroke. This is alsotrue of the pairs of cylinders'S, 5; 4, 7 and 3, 2.

The hemispherical combustion chambers 13 of the cylinders 10 are bypreference each provided with a single inlet opening or port 18 closedby an inlet valve 19 and with a single smaller exhaust outlet or port 20closed by an exhaust valve 21, these valves being arranged transverselyof the longitudinal axis 22 of the engine and at a substantial angle,for instance, 60 to each other, and preferably on a great arc of thespherical segment forming the combustion chamber 13. As seen in Figure2, all of the inlet openings 18 are in longitudinal alignment and all ofthe exhaust openings 20 are similarly arranged.

The inlet and exhaust valves of both banks of the engine are operablefrom a single camshaft 24 located above the crankshaft 15, the camshaftactuating suitable tappet mechanism associated with the push rods 25 and26 of the inlet and exhaust valve mechanisms respectively which in turnactuate respectively the inlet valve rocker arms 27 and exhaust valverocker arms 28, these rocker arms actuating in turn the normallyspring-held closed valves 19 and '21.

By preference, the camshaft 24 ,is usually arranged to open therespective inlet valves 19 before top dead center position of the pistonand to close the exhaust valves after top dead center position of thepiston so as to maintain the intake valve open during a substantialportion of crank rotation and to maintain the exhaust valve open longenough to obtain an overlap between opening of the inlet valve andclosing of the exhaust valve of each cylinder.

The intake or induction manifold of my invention generally referred toby the numeral 29, comprises an integral structure having two systems ofconduits or passages indicated diagrammatically and generally in Figure2A by the reference numerals 30, 32. The system 30 comprises fourair-fuel passages or conduits generally referred to by the numerals 34,36, 38, and 40 communicating at one end with a manifold intake or riserpassage 42 fed by the single barrel riser or the carburetor X (seeFigure 3) and preferably located on the longitudinal axis 22 of themanifold and approximately on a transverse line midway the cylinders 1and 4 and communicating at the opposite ends with the intake passages 43leading to the intake ports 18 for the cylinders 1, 4, 6, and 7respectively. The system 32 comprises four airfuel passages or conduitsgenerally referred to by the numerals 44, 46, 48, and 50 communicatingat one end with a manifold intake or riser passage 52 fed by the singlebarrel of the carburetor Y, preferably located on the longitudinal axis22 and approximately on a transverse line midway the cylinders 5 and 8and communicating at the opposite ends with the intake passages 43leading to the intake ports 18 for the cylinders 2, 3, 5, and 8.

As seen in Figures 2 to 10, the carburetors X and Y are mounted onraised pads or bases 54, 56 respectively of the manifold, defining theriser passages 42, 52, the latter being in vertical alignment with thebarrels 58, 60 respectively, of the carburetors X and Y from which gasor air-fuel mixture may be delivered to the risers 42, 52 under controlof bladed throttle members 62, 64 located in the barrels 58, 60respectively, and adapted to assume any condition from fully open tofully closed throttle. These throttle members may be controlled in anysuitable manner preferably conjointly.

The pads 54, 56 are carried by the air-fuel conduits aforesaid, these inturn connecting with longitudinally extending manifold mounting portionsor flanges 66, 68 provided with inclined finished under faces 70, 72which are downwardly converging and which coincide with mounting faces74, 74a of the cylinder heads 12, 12a when seating the manifold. It willbe noted that these flanges are somewhat longitudinally offset withrespect to each other and symmetrically arranged relative to the risers42, 52.

The manifold 29 is secured in position on the cylinder heads 12, 12awith intervening gaskets 75 by bolts (not shown) which pass through themounting holes 76 of the flanges into threaded holes (not shown) of thecylinder heads.

As seen in Figure 8, the riser passage 42 for the carburetor X isshorter than the riser passage 52 for the carburetor Y. The riser 42comprises a cylindrical portion 42a and an enlarged base portion forminga distri bution chamber 77 into which the conduits 34, 36, 38, and 40open. The riser passage 52 comprises a similar but somewhat longercylindrical portion 52a and a base portion forming a chamber 78 intowhich the conduits 44, 46, 48 and 50 open in a lower plane or level thanthe conduits of the riser 42 open into the chamber 77. Moreover, it willbe observed from Figures 2-10 that the air-fuel conduits of my inventionon one side of the axis 22 are when viewed in plan symmetrical withthose on the opposite side, that each is preferably of generally thelatter on a line normal to the axis 22 and terminating in an opening 82in the flange 66 coinciding with the entrance of the intake passage 43for cylinder No. 1. In a similar but opposite manner and starting at asomewhat lower level the conduit 50 extends from its entrance opening 84in the chamber 78 of the riser 52 and terminates in an opening 86 in theflange 68 coinciding with the entrance opening of the intake passage 43of cylinder No. 8. It will be observed, however, by reference to Figures5 and 6, for example, that the passage 50 where it extends from itsriser 52 and for some distance prior to meeting the intake passage 43 atits outlet 86 is at a lower level than the conduit 34 where the latterextends from the riser 42, chamber 77. This facilitates pyramiding orstacking of certain conduits or passages, and in this connection, thepassages 34, 36, 38, and 40 emanating from the chamber 77 of the riser42 may be termed the upper level air-fuel passages, these being in theuppermost conduit plane of the manifold, whereas the passages 44, 46,48, and 50 emanating from the chamber 78 of the riser 52 may be termedthe lower level air-fuel passages, these being in the intermediateconduit plane of the manifold,

The upper level passages 36, 38 are in juxtaposition to each other wherethey emanate from the chamber 77 of the riser 42 and have adjacentrectangular entrance openings 88, 89 respectively. The conduit 36 asseen in Figure 2 is of a generally reverse curve shape. It extendsobliquely from the riser 42 until past the conduit 44 and then dips downas seen in Figure 7 and terminates in an opening 90 coinciding with theentrance of the intake passage 43 of cylinder No. 4. The conduit 38extends alongside the conduit 36 and over the conduit 44. It has acommon vertical wall 91 with the conduit 36 until these conduitsseparate and diverge from each other at the point where the conduit 36turns outwardly on a line normal to the axis 22 to meet the intakepassage of cylinder No. 4. The conduit 38 continues on a linesubstantially parallel to the axis 22 and then turns outwardly generallynormal to the axis 22 when abreast cylinder No. 6 and turns downwardlyas seen in Figure 6 to terminate in an opening 92 coinciding with theentrance of the intake passage 43 for cylinder No. 6.

The conduits 46, 48 extend between their risers 52 and mounting in aflange manner similar to that which the conduits 36, 38 extend betweenthe chamber 78 of the riser 52 and mounting flange 66 but in an oppositedirection and at the lower air-fuel passage level aforesaid, they being-below the air-fuel passage 40. These conduits 46, 48 have juxtaposedentrance openings 93, 94 in the chamber 77 of the riser 52 and terminalopenings 95, 96 respectively in the flange 66 where they coincide withthe entrances of the intake passages 43 for cylinders Nos. 3 and 5respectively. As in the case of the conduits 36, 38 the conduits 46, 48have a common vertical wall 97 extending a portion of their length fromthe riser 52.

The conduit 40 extends at the upper air-fuel level from its entranceopening 98 in the chamber 77 of the riser 42 along a path generallyparalleling the axis 22 and over the conduit 46 crossing the conduit 48and curving outwardly when past intermediate cylinders 5 and 7 anddownwardly when past the conduit 48 to terminate in an opening 99coinciding with the intake passage 43 for cylinder No. 7.

It will be observed that the entrance opening 98 of the conduit 40 isjuxtaposed the entrances 80 and 89 of the conduits 34 and 38respectively; and that the entrance openings 80, 98, 89, and 88 arearranged one in juxtaposition to the next at the level of the chamber77. Moreover, as seen in Figure 7, for example, the upper level conduit40 has a common horizontal wall 100 with the lower level air-fuelconduits 46 and 48 where it is immediately above the same. It will alsobe seen that the vertical wall 101 of the conduit 40 intersects at 102with the vertical wall 103 of the conduit 38 to form a common verticaledge for the juxtaposed openings 98 and 89 of these conduits, that thevertical wall 1640f the conduit 40 intersects at 105 with the verticalwall 106 of the conduit 34 to define a common edge of thejuxtaposedentrance openings 93 and 80 of these conduits and that theterminal end 99a of the common vertical wall 91 of the conduits 36, 38provides a common edge for the juxtaposed entrance openings 88, 89 ofthese conduits in the chamber 77.

The lower level air-fuel conduit 44 extends between its chamber 73 ofthe riser 52 and its mounting flange 68 in the same manner to that inwhich the conduit 40 extends from its riser 42 but below the conduits36, 38. It has an entrance opening 107 in the chamber 78 of the riser 52and a terminal opening 108 in the flange 68 where it coincides with theintake passage 43 of cylinder No. 2.

The entrance openings 84, 107, 93, and 94 to the chamber 78 of riserpassage 52 are at the same level and one juxtaposed the other. Thus theentrance 197 is juxtaposed the entrance 84 and has a common verticaledge 110 formed by the intersection of the vertical wall 112 of theconduit 44 with a vertical wall 114 of the conduit 50; the entrance 107is also juxtaposed the entrance 93 and these have a common vertical edge116 formed by intersection of the vertical wall 118 of the conduit 44and the vertical wall 129 of conduit 46 and the entrance 93 of conduit46 is juxtaposed the entrance 94 of conduit 48 and these have a commonterminal edge 122 determined by their common vertical wall 97.

As seen in Figures 4 and 7, the lower level air-fuel conduit 44 crossesthe upper conduit 36 and substantially coincides part way with the upperlevel conduit 38 so as to have in part a common horizontal wall 124 withthe conduits 36, 38.

As previously noted, the manifold of this invention lends itselfparticularly to water heating of the carburetor riser hot spot andalthough exhaust gas heating may be used therefor, water heating ispreferred since it avoids the need of a pair of exhaust gas crossoverpassages in the cylinder head of each bank. For the purpose of waterheating the carburetor intake riser passages, I provide intermediateeach of the end pairs of cylinders of each bank in the cylinder headsthereof, suitable water outlet passages 129 which conduct water tosuitable passages to be described of the manifold 29 and providedadjacent the risers 42, 52 thereof and from which the water is returnedto the radiator of the vehicle.

As seen in Figure 2 and Figures 8 to 10, water may enter the manifoldstructure 29 through openings 130 and 132 in the mounting flange 66 ofthe left hand cylinder bank and through openings 131 and 133 in themounting flange 68 of the right hand cylinder bank. The openings 130,131 communicate with a cross conduit or passage 135 of rectangular shapeseen best in Figures 2 and 10 which passes immediately below and injoinder with the chamber 78. This passage 135 has a common horizontalwall 137 with the chamber 78 of the riser 52 by which to communicateheat to the passage riser. Since the air-fuel passages 44, 46, 48, and Semanate from the chamber 78 at the lower air-fuel passage level and thecross passage 135 must transverse these air-fuel passages, the level ofthe cross passage 135 is below that of these air-fuel passages 44, 46,48, and 60 and may be designated the lowermost or bottom conduit planeof the manifold 29. Due to the offset between the cylinders of theopposite banks of the engine the cross passage 135 as seen in Figure 2,has its portions or branches on the opposite side of the axis 22 offsetsomewhat from each other. As also seen in Figure 2, the cross passage135 extends intermediate the cylinders Nos. and 7 of the left hand bank,and cylinders Nos. 6 and 8 of the right hand s The second pair of waterinlet apertures 1 32 and 133 are, as seen in Figure 2, located in themounting flanges 66 and68 respectively, intermediate the cylinders Nos.1 and 3 of the left hand bank, and the cylinders Nos. 2 and 4 of theright hand bank. These apertures are connected by a cross passage 138which, as seen in Figures 2 and 9 and by reference to Figure 10, extendstransversely from the aperture 133 to just past the axis 22 of themanifold and at the same level as the water passage extends across themanifold. This portion or branch of the water passage 138, identified bythe numeral 140, has its top horizontal wall 142 in the same planecommon with the bottom wall 144 of the conduit 44. Just past the conduit44 the water passage 138 extends upwardly and then horizontally at theintermediate conduit level to connect the water inlet 132 of the lefthand bank. The vertical portion 146 of the water passage has a verticalWall 150 common with a vertical wall of the conduit 44 and has ahorizontal wall 152 common with the floor of the chamber 77 of the riser42 by which to directly communicate heat thereto. Connecting the twocross water passages 135 and 138 is a central longitudinal water passageor chamber 154 in the plane of the passage 135 and which is defined byside Walls 156 and 157 seen in Figure 2 and bottom wall 158, and a topwall 160 seen in Figure '8, the latter wall lying intermediate thelongitudinally directed air-fuel passages 38, 4t 44, and 46 of Figure 2.Moreover as seen in Figures 2 and 8 the central chamber 154 and thecross water passage 138 are connected by a passage 162 which extendsupwardly therefrom, it terminating in an outlet 164 having a mountingface 165 for receiving a water connection with the radiator. It will beevident that by the described water system, adequate heating will beconducted to the riser passages of the spaced carburetors.

As previously described, I have found it possible to controlover-enrichment of certain cylinders during low speed operation 'by theuse of metering means between the intake risers of the manifold whoseeffect is to damp out high pulsations. In Figures 11 and 12 I have shownone form of accomplishing this result and which comprises a pair oftubes 170, 172 extending between the bosses 54 and 56 of the manifoldand opening into the riser passages 42, 52 so as to efiect a limitedcommunication or passage 173 between the risers. It will be evident fromFigure 12 that I effect this result by providing a pair oftube-receiving stepped bores 174 entirely across the boss 56 and throughone side of the boss 54. It will be observed that the portions 175, 176of the bore 174 are somewhat larger than the remaining portions 177, 178and larger than the tubes 170, 172. Such facilitates easy assembly ofthe tubes in the portions 177, 178 which support them. The portions ofthe bores 174 are threaded at their outer end to receive plugs 178 afterthe tubes are assembled in position. A pair of tubes is preferred inorder to obtain the lowest possible silhouette for the manifoldstructure. It will be understood, however, that a single tube may beemployed if desired. In the present showing for a 331 cu. in. engine Ihave found that two tubes of in. inside diameter give optimum results.The total cross-sectional area of the passages 173 of these tubes is 0.3square inch.

As seen in Figures 1 and 3, the carburetors X and Y are preferably ofthe type utilizing side-type air cleaners which, as seen, are preferablypositioned with their air intake faces at an angle to the horizontalaxis 22 of the manifold and parallel to each other so as to makepossible use 'of the largest air cleaner surface. It will be understoodthat concentric-type vertical air cleaners of standard construction mayalso be used if desired.

Some idea of the increase in midspeed torque possible with the novelmanifold of my invention will be evident from the following comparisonof two test runs at wide open throttle with a 331 cu. in. V-8 engine ofthe character described. Run No. D was made using a conventionalmanifold of the general type shown in the application of Carpent'ier etat, Serial No. 283,198, filed April 19,- 1952, and now Patent No.2,686,506, granted August 17, 1954, and employing a conventional CarterW. C. D. 9315 dual barrel carburetor having 1%! venturis, while run No.S employed the manifold of the subject invention employing two Ball andBall E7T1 adjustable jet carburetors with conventional concentric aircleaners No. 919801, the carburetors having 1 venturis.

Run No. D Run No. S

Speed Torque B. H. P. Torque B. H. P.

(lb. ft.) (1b. 11:.)

From this test data it will be apparent that the manifold of the subjectinvention produces a considerable increase in midspeed torque.

From the foregoing description of my invention it will be apparent thatI have provided a novel manifold structure and system capable ofproviding optimum midspeed torque and particularly adapted for use fortruck engines. It will be understood that various changes andmodifications may be made in the novel features of my invention withoutdeparting from the intent and spirit thereof and all such changes andmodifications as are embraced by the appended claims and equivalentsthereof are to be included.

I claim:

1. An intake manifold for an engine having opposite cylinder banks eachincluding a plurality of cylinders, said manifold comprising oppositelongitudinally extending portions for mounting said manifold on saidengine banks, an intermediate portion on which to support a pair of fuelsupply means, and conduit means connecting said mounting portions andsaid intermediate portion, a pair of longitudinally wide spaced intakeriser passages on said intermediate portion, one transversely adjacentan end cylinder of one bank, and the other transversely adjacent the endcylinder at the opposite end of the same bank, one of said pair of riserpassages each fed by one of said pair of fuel supply means and the otherof said pair of riser passages to be fed by the other of said pair offuel supply means, a plurality of spaced apertures in said mountingportions arranged longitudinally thereof, there being one such aperturefor each cylinder, and a plurality of air-fuel passages provided by saidconduit means between said apertures and said risers, there being anindependent passage directly connecting each aperture with a riserpassage; half the number of passages connecting with one riser and 'halfconnecting with the other.

2. An intake manifold for an engine having opposite cylinder banks eachincluding a cylinder :head and a plurality of cylinders, said manifoldcomprising opposite longitudinally extending flange portions formounting said manifold to said cylinder heads, an intermediate portionon which to support a pair of single barrel fuel supply means, andconduit means connecting said mounting portions and said intermediateportion, a pair of longitudinally wide spaced intake riser passages onsaid intermediate portion, one transversely adjacent an end cylinder ofone bank and the other transverselyadjacent the end cylinder at theopposite end of the same bank, one of said pair of riser passages eachfed by one of said pair of fuel supply means and the other of said pairof riser passages to be fed by the other of said pair of fuel supplymeans, a plurality of spaced apertures in each of said mounting portionsarranged longitudinally thereof 0116 opposite each cylinder, and aplurality of airfuel passages provided by said conduit means, eachindependently connecting an intake riser with a different aperture,there being one such passage for each aperture and half the number ofsaid pas-sages directly connecting only with one of said riser passageswhile the other half thereof directly connect only with the other ofsaid riser passages.

3. An intake manifold for an engine having opposite cylinder banks eachincluding a cylinder head and .a plurality of cylinders, said manifoldcomprising opposite longitudinally extending flange portions formounting said manifold to said cylinder heads, an intermediate portionon which to support a pair of single barrel fuel supply means, andconduit means connecting said mounting portions and said intermediateportion, a pair of longitudinally spaced intake riser passages on saidintermediate portion, one transversely adjacent an end cylinder of onebank and the other transversely adjacent the end cylinder at theopposite end of the same bank, each riser passage including adistribution chamber at the lower end thereof, that of one riser beingin a lower plane than the chamber of the other, a plurality ofperipherally adjacent apertures in each of said chambers, a plurality ofspaced apertures in each of said mounting portions arrangedlongitudinally thereof, one opposite each cylinder, and a plurality ofair-fuel passages provided by said conduit means, each connecting achamber aperture with a mounting aperture, no two of said passagesconnecting with the same apertures and half the number of said passagesbeing associated with one riser chamber and the remainder with the otherriser chamber.

4. An intake manifold as claimed in claim 3 wherein some of the air-fuelpassages associated with each riser chamber connect with the aperturesof the mounting portion of one bank and the remainder with apertures ofthe mounting portion of the other bank.

5. An intake manifold for an engine having opposite cylinder banks eachincluding a cylinder head and four cylinders, the cylinders of one bankstarting from one end of the engine being successively numbered forreference herein 1, 3, 5 and 7 and being respectively locatedsubstantially opposite to those cylinders in the other bank whichstarting from the same end of the engine are numbered 2, 4, 6 and 8,said manifold comprising opposite mounting portions for mounting saidmanifold to said bank, a pair of longitudinally spaced intermediateportions each containing an intake riser passage, one locatedintermediate cylinders 5 and 8 and the other intermediate cylinders 1and 4, air-fuel conduit portions connecting said intermediate portionsand said mounting portions, said conduit portions providing independentair-fuel passages between one riser passage iand said mounting portionsfor feeding cylinders 1, 4, 6, and 7 and corresponding independentair-fuel passages between the other riser passage and said mountingportions for feeding cylinders 8, 5, 3, 2. I

6. An intake manifold for an engine having opposite cylinder banks eachincluding a cylinder head and four cylinders, the cylinders of one bankbeing successively numbered for refieren'ceyherein 1, 3, 5, 7 and beingrespectively located substantially. opposite to those cylinderssuccessively numbered 2, 4, 6, 8 in the other bank, said manifoldcomprising opposite mounting portions for mounting said manifold to saidbanks, a pair of longi tudinally spaced intermediate portions eachcontaining an intake riser passage, one of said riser passages beinglocated intermediate cylinders 5 and 8, and the other being locatedintermediate cylinders 1 and 4, conduit portions connecting saidintermediate portions and said mounting portions, said conduit portionsproviding independent passages each haVing an independent inlet openingin one of said riser passages and an independent terminal opening in oneof said mounting portions adjacent -a cylinder of the ban-k mountingsuch mounting portion, said terminal'opening substantially coincidingwith the inlet of the intake passage to this cylinder, some of saidindependent passages being between one of said riser passages and thesaid mounting portion terminal openings thereof adjacent cylinders 1, 4,6, 7 and others corresponding thereto when viewed in plan being betweenthe other riser passage and the said mounting portion terminal openingsthereof adjacent cylinders 8, 5, 3, the inlet openings for said passagesin one riser being in a lower plane than those of the other riserpassage, and one of said conduits defining a passage from one riserbeing in part immediately above a pair of conduits defining passagesfrom theother riser and a portion of a further conduit defining apassage from said other "riser corresponding to said passage defined bysaid one conduit being immediately below a pair of other conduitsdefining passages from said one riser corresponding to those defined bysaid first mentioned pair of conduits.

7. An intake manifold as claimed in claim 6 wherein each intake riserpassage includes a distribution chamber and each conduit passageconnects with its riser passage at said chamber.

8. An intake manifold as claimed in claim 6 wherein the inlet openingsfor the conduit passages for cylinders l, 4, 6, and 7 are peripherallyspaced around the riser passage with which these passages connect andare adjacent the lower end of said passage and wherein the inletopenings for the conduit passages for cylinders 8, 5, 3, 2 are similarlydisposed with respect to the riser passage with which they connect.

'9. An intake manifold as claimed in claim wherein the inlet openings ofthe conduit passages connecting with each riser passage are adjacenteach other and wherein the said conduit passages for the pairs ofcylinders 3 and 5, and 4 and 6 respectively, have a common vertical wallterminating at the riser passage with which their inlet openings areassociated.

10. An intake manifold for an engine having opposite cylinder banks eachincluding a cylinder head and four cylinders, the cylinders of onebankstarting from one end of the engine being successively numbered forreference herein 1, 3, 5, and 7 and being respectively locatedsubstantially opposite to those cylinders in the other bank whichstarting from the same end of the engine are numbered 2, 4, 6, and 8,said manifold comprising opposite mounting portions for mounting saidmanifold to said bank, a pair of longitudinally spaced intermediateportions each containing an intake riser passage, one locatedintermediate cylinders 5 and 8 and the other intermediate cylinders land 4, air-fuel conduit portions connecting said intermediate portionsand said mounting portions, said conduit portions providing independentair-fuel passages between one riser passage and said mounting portionsfor feeding cylinders l, 4, 6, and 7 and corresponding independentair-fuel passages between the other riser passage and said mountingportions for feeding cylinders 8, 5, 3, 2, said risers each including adistribution chamber into which the air-fuel passages connecting withthese risers open, said chambers being in different planes, and theair-fuel passages emanating therefrom being in different planes, certainof said passages from one chamber having longitudinally extendingportions which are stacked with respect to other passages from the otherchamber, a pair of water conduits defining water passages extendingtransversely between said mounting portions in planes below said riserpassages each such conduit having an upper wall portion common with thelower wall of the riser passage which it traverses and a longitudinallyextending water conduit interconnecting said transverse water conduitsdefining a water passage -12 interconnecting said-traverse waterpassages, the opposite endsof said transverse water passages being openand defining water inlets and one end of said longitudinal water passagebeing open and defining a water outlet.

11. A manifold as claimed in claim 10 wherein said water inlet is in aportion of said longitudinally extending water conduit that extendsoutwardly past one of said riser passages.

12. An intake manifold for an engine having opposite cylinder banks eachincluding a plurality of cylinders, said manifold comprising oppositeportions for mounting said manifold on said engine banks, anintermediate portion on which to supporta pair of fuel supply means,conduit means connecting said mounting portions and said intermediateportion, a pair of longitudinally spaced intake riser passages on saidintermediate portion for connecting with said fuel supply means, one ofsaid riser passages being transversely adjacent an end cylinder of onebank and the other transversely adjacent the end cylinder at theopposite end of the same bank, said conduit means defining a pluralityof air-fuel passages extending between said mounting portions and therisers of said inter-mediate portion, half the number of said passagesconnecting with one riser, and half connecting with the other riser, andmetering control means interconnecting said riser passages.

13. An intake manifold for an engine having opposite cylinder banks eachincluding a plurality of cylinders, said manifold comprising oppositeportions for mounting said manifold on said engine banks, anintermediate portion on which to support a pair of fuel supply means,conduit means connecting said mounting portions and said intermediateportion, a pair of longitudinally spaced intake riser passages on saidintermediate portion for connecting with said fuel supply means, one ofsaid-riserpassages being transversely adjacent an end cylinder of onebank and the other transversely adjacent the end cylinder at theopposite end'of the same bank, said conduit means defining a pluralityof air fuel passages extending between said mounting portions and therisers of said intermediate portion, half the number of said passagesconnecting with one riser, and half connecting with the other riser, andlongitudinal passage means having a cross-sectional area of lessthanone-half square inch interconnecting said risenpassages.

14. An intake manifold for an engine having opposite cylinder banks eachincluding a plurality of cylinders, said manifold comprising oppositeportions for mounting said manifold on said engine banks, a pair oflongitudinally spaced intermediate portions on which to support a pairof single barrel fuel supply means, conduit means connecting saidmounting portions and said intermediate portions, each of saidintermediate portions having an intake riserpassage connecting with thefuel supply means thereon and said conduit means providing air-fuelpassages between said riser passages and said mounting portions, therebeing an independent air-fuel passage for connecting with each cylinderof the engine and half the number of said passages connecting with oneriser and the remainder connecting with the other riser and tubularmetering means extending between said intermediate portions and openinginto said riser passages for interconnecting the same.

15. An intake manifold as-claimed in claim 14 wherein said tubularmetering means comprises a plurality of tubes.

References Cited in the file of this patent UNIT ED STATES PATENTS2,640,471 Ha'ltenberger June 2, 1953

